1,363,524 research outputs found
Pollen physiology and fertilisation in Vicia Faba L
No full textAbstract In many legume crop species, early-formed fruits or those located closest to the photosynthate are more likely to mature than other fruits. This is so in the Vicia faba crop. Based on physiological, nutritional and genetical aspects of seed development, several hypotheses are documented. However, Vicia faba pollen fertility has not been adequately studied. Thus, a series of experiments, consisting of studies of both in vitro and in vivo pollen viability, pollen tube growth and fertilisation ability were conducted using highly inbred lines (6-13 generations). Some of the in vivo experiments were conducted under Ethiopian field conditions. In some lines, even a low level of stress at 20 ºC for 4h at 100% relative humidity (RH) caused a dramatic drop in mean percent pollen germination. The overall results indicated that there was considerable variation (p≥0.001) among the Hues studied, in response to high temperature (20 to 35 C) and 100% RH. Vicia faba pollen showed high variability in fertility level. Overall significant differences exist in fertility (p≥0.01) among the genotypes studied. A fertility gradient exists along the stem: in most genotypes the fertility declining towards the upper nodes. In all of the genotypes, the first nodes carried more highly fertile pollen than the middle and the last flowering nodes. Also the middle nodes were more highly productive than the last nodes in all the genotypes. Thus, success of fertilisation depends to a degree on the source of pollen used. In an experiment concerning pollen storage, freshly dehiscent anthers desiccated at 25 C/6h and freeze dried for 45min, stored in either LN2 or at -80 ºC, gave more than 80% viability after 9 months of storage. Desiccation at RT for 24h and storage in either LN2 or at -80 C and at -20 C, still maintained pollen viability ≥80%. Mixed pollination studies conducted indicated that pollen from one or other of each pair of inbred fines, mixed on an equal weight basis, performed better as pollen parents on some maternal fines than on others. The importance of these findings with respect to synthetic variety and hybrid seed production in the text is discussed. The probable existence of genetic self-incompatibility is also discussed
Construction of a comparative genetic map in faba bean (Vicia faba L.); conservation of genome structure with Lens culinaris
No full textBackground
The development of genetic markers is complex and costly in species with little pre-existing genomic information. Faba bean possesses one of the largest and least studied genomes among cultivated crop plants and no gene-based genetic maps exist. Gene-based orthologous markers allow chromosomal regions and levels of synteny to be characterised between species, reveal phylogenetic relationships and chromosomal evolution, and enable targeted identification of markers for crop breeding. In this study orthologous codominant cross-species markers have been deployed to produce the first exclusively gene-based genetic linkage map of faba bean (Vicia faba), using an F6 population developed from a cross between the lines Vf6 (equina type) and Vf27 (paucijuga type).
Results
Of 796 intron-targeted amplified polymorphic (ITAP) markers screened, 151 markers could be used to construct a comparative genetic map. Linkage analysis revealed seven major and five small linkage groups (LGs), one pair and 12 unlinked markers. Each LG was comprised of three to 30 markers and varied in length from 23.6 cM to 324.8 cM. The map spanned a total length of 1685.8 cM. A simple and direct macrosyntenic relationship between faba bean and Medicago truncatula was evident, while faba bean and lentil shared a common rearrangement relative to M. truncatula. One hundred and four of the 127 mapped markers in the 12 LGs, which were previously assigned to M. truncatula genetic and physical maps, were found in regions syntenic between the faba bean and M. truncatula genomes. However chromosomal rearrangements were observed that could explain the difference in chromosome numbers between these three legume species. These rearrangements suggested high conservation of M. truncatula chromosomes 1, 5 and 8; moderate conservation of chromosomes 2, 3, 4 and 7 and no conservation with M. truncatula chromosome 6. Multiple PCR amplicons and comparative mapping were suggestive of small-scale duplication events in faba bean. This study also provides a preliminary indication for finer scale macrosynteny between M. truncatula, lentil and faba bean. Markers originally designed from genes on the same M. truncatula BACs were found to be grouped together in corresponding syntenic areas in lentil and faba bean.
Conclusion
Despite the large size of the faba bean genome, comparative mapping did not reveal evidence for polyploidisation, segmental duplication, or significant rearrangements compared to M. truncatula, although a bias in the use of single locus markers may have limited the detection of duplications. Non-coding repetitive DNA or transposable element content provides a possible explanation for the difference in genome sizes. Similar patterns of rearrangements in faba bean and lentil compared to M. truncatula support phylogenetic studies dividing these species into the tribes Viceae and Trifoliae. However, substantial macrosynteny was apparent between faba bean and M. truncatula, with the exception of chromosome 6 where no orthologous markers were found, confirming previous investigations suggesting chromosome 6 is atypical. The composite map, anchored with orthologous markers mapped in M. truncatula, provides a central reference map for future use of genomic and genetic information in faba bean genetic analysis and breeding
Aspects of structure and functionality in legumin and vicilin from vicia faba seeds
No full textSoy beans command a large proportion of the vegetable protein market of the food processing industry; however, their cultivation is limited by climatic factors. A crop able to compete in these markets, but suited to growth in cooler, temperate conditions would have political and economic advantages for Europe. One such crop under consideration is Vicia faba minor. A new faba bean line (IVS-G),developed by a breeding programme at Durham University, was compared to an established commercial variety (Maris Bead) for chemical, physical and functional characteristics. A selection of processing methods was used to produce proteinaceous materials equivalent to soy products already on the commercial market. The methods used were defatting, air-classification, and the production of isolates, proteinates and micellar protein preparations. The materials were assessed and compared to soy products for functionality in tests designed to assess solubility, gelling, foaming and emulsifying properties. The storage proteins, legumin and vicilin, are the major protein constituents of the bean seed, and their structural and functional properties were also investigated. The bean products had similar functional properties to equivalent soy products, when protein contents were also similar. However, the higher initial in vivo protein content of the soy bean does give the latter a competitive advantage. Also, the marketing of by-products of faba bean, eg. Starch and fibre, may prove difficult
Alameda : un modelo estructural-funcional del cultivo de Vicia faba L
No full textEl modelo estructural-funcional ALAMEDA de un cultivo de Vicia faba L se ha construido dentro del formalismo de los sistemas de Lindenmayer o sistemas-L, es decir, dentro de unas de las teorías metaméticas del desarrollo relacionada con las gramáticas de crecimiento. ALAMEDA incluye explícitamente la morfología de las plantas y de la arquitectura de la cubierta del cultivo complementando a los modelos clásicos de simulación de cultivos, que simulan la cubierta como un medio homogéneo.su conexión a los modelos de procesos es clave para su aplicación en agronomía y en este trabajo se inicia y se habilita esta posibilidad. El objetivo del trabajo es la obtención de una base de datos morfológica detallada sobre Vicia faba L. Que permite la escritura de un modelo estructural, así como su conexión con un modelo de crecimiento empírico, y una primera validación a través de la simulación del área foliar. La descripción cualitativa y cuantitativa de la geometría y topología de plantas y cultivos se ha obtenido de ensayos en campo y en ensayo bajo condiciones controladas. Las técnicas utilizadas para la obtención de datos han sido las usadas en fisiología de cultivos junto con la digitalización electromagnética. Esta técnica permitió capturar la geometría y topología de la cubierta así como su evolución a lo largo del ciclo. La alta plasticidad de las habas dificulta la obtención de relaciones universales sobre número y tamaño de los órganos, encontrándose sin embargo que información válida para la planta entera sobre parámetros morfológicos como longitud, área foliar y ángulos, puede derivarse de observaciones hechas únicamente en el tallo principal o en uno de los secundarios. La expresión del filocrono y de las fenofases en unidades térmicas posibilitó la evolución hacia el modelo estructural-funcional, al permitir la conexión con un modelo de crecimiento. La simulación del área foliar del cultivo se realiza en ALAMEDA por órganos o módulos, permitiendo la localización espacial (3D) de dichos órganos y la simulación de la evolución de sus dimensiones. El modelo ALAMEDA se calibró con una de las series de datos disponibles de los ensayos de campo. En las primeras versiones del modelo, la simulación de la superficie foliar y de la intercepción de radiación fotosintéticamente activa no mostró diferencias significativas en comparación con las determinaciones de campo. En la última versión (ALAMEDA V.3), ya en fase estructural-funcional, las simulaciones de las longitudes de los órganos vegetativos y del área foliar se contrastaron con ensayos de diferentes fechas de siembra. La calidad de la simulación del área foliar y de su distribución en la cubierta es función de la simulación de dichas longitudes. La vocación final de ALAMEDA es el progreso hacia una modelización más mecanicista. La conexión con el modelo de crecimiento ha demostrado la viabilidad de este enfoqu
New direct contact approach to evaluate soil genotoxicity using the Vicia faba micronucleus test.
No full textA method to assess micronucleus (MN) induction in Vicia faba roots by direct contact exposure to a solid matrix was developed. The procedure comprised a 5-d germination period, as in the well-known method using aqueous extracts. However, the seeds were here sown directly into the test soil whereas a culture period is necessary before exposing seedlings to a liquid medium. One soil under forest and two contaminated soils from areas affected by industrial installations and a coke works were used. Three durations of direct exposure were tested: 2, 5 and 7 d. The optimal duration was evaluated at 2 d to observe maximal MN induction without observing toxicity symptoms. The methodology using aqueous extracts was applied to the same three soils: MN frequency was higher than in the direct contact assay but the ratios of MN frequencies from tested soils in comparison to the negative control were lower. However, for each soil, both the direct contact method and the aqueous extract exposure led to the same risk assessment diagnosis. The evaluation of a concentration range of a polycyclic aromatic hydrocarbons (PAH)-contaminated soil showed a dose-dependent MN frequency when the seeds were allowed to germinate before sowing in the soil: the soil genotoxicity was the highest at intermediate doses. The direct contact method was found to be rapid, sensitive and well suited to the evaluation of soil qualit
Lead-induced DNA damage in Vicia faba root cells: Potential involvement of oxidative stress
No full textGenotoxic effects of lead (0–20 µM) were investigated in whole-plant roots of Vicia faba L., grown hydroponically under controlled conditions. Lead-induced DNA damage in V. faba roots was evaluated by use of the comet assay, which allowed the detection of DNA strand-breakage and with the V. faba micronucleus test, which revealed chromosome aberrations. The results clearly indicate that lead induced DNA fragmentation in a dose-dependant manner with a maximum effect at 10 µM. In addition, at this concentration, DNA damage time-dependently increased until 12 h. Then, a decrease in DNA damages was recorded. The significant induction of micronucleus formation also reinforced the genotoxic character of this metal. Direct interaction of lead with DNA was also evaluated with the a-cellular comet assay. The data showed that DNA breakages were not associated with a direct effect of lead on DNA. In order to investigate the relationship between lead genotoxicity and oxidative stress, V. faba were exposed to lead in the presence or absence of the antioxidant Vitamin E, or the NADPH-oxidase inhibitor dephenylene iodonium (DPI). The total inhibition of the genotoxic effects of lead (DNA breakage and micronucleus formation) by these compounds reveals the major role of reactive oxygen species (ROS) in the genotoxicity of lead. These results highlight, for the first time in vivo and in whole-plant roots, the relationship between ROS, DNA strand-breaks and chromosome aberrations induced by lead
Assessment of the genotoxicity of quinolone and fluoroquinolones contaminated soil with the Vicia faba micronucleus test
No full textThe genotoxicity of quinolone and fluroquinolones was assessed using the micronucleus (MN) test on Viciafaba roots by direct contact exposure to a solid matrix. Plants were exposed to quinolones (nalidixic acid) and fluoroquinolones (ciprofloxacin and enrofloxacin) alone or mixed with artificially contaminatedsoils. Four different concentrations of each of these antibiotics were tested (0.01, 0.1, 1 and 10 mg/Kg) for nalidixic acid and (0.005, 0.05, 0.5 and 5 mg/Kg) for ciprofloxacin and enrofloxacin. These antibiotics were also used in mixture. Exposure of Vicia faba plants to each antibiotic at the highest two concentrations showed significant MN induction. The lowest two concentrations had no significant genotoxic effect. The mixture of the three compounds induced a significant MN induction whatever the mixture tested, from 0.02 to 20 mg/Kg. The results indicated that a similar genotoxic effect was obtained with the mixture at 0.2 mg/Kg in comparison with each molecule alone at 5–10 mg/Kg. Data revealed a clear synergism of these molecules on Vicia faba genotoxicity
Assessment of the genotoxicity of olive mill waste water (OMWW) with the Vicia faba micronucleus test
No full textThe present study concerns the genotoxicity of olive mill waste water (OMWW) generated in mills producing olive oil in Morocco. The Vicia faba micronucleus test was used to evaluate the genotoxicity of OMWW and the six major phenolic compounds identified by HPLC in this effluent. Five dilutions of OMWW were tested: 0.1, 1, 5, 10 and 20%. Maleic hydrazide was used as a positive control. The results showed that OMWW was genotoxic at 10% dilution. In order to investigate the components involved in this genotoxicity, the six major phenols present in this effluent, oleuropein, gallic acid, 4-hydroxyphenyl acetic acid, caffeic acid, paracoumaric acid and veratric acid, were studied at concentrations corresponding to the genotoxic concentration of the OMWW itself. Two phenols, gallic acid and oleuropein induced a significant increase in micronucleus frequency in Vicia faba; the four other phenols had no significant genotoxic effect. These results suggest that under the experimental conditions of our assay, OMWW genotoxicity was associated with gallic acid and oleuropein
Lead-induced genotoxicity to Vicia faba L.roots in relation with metal cell uptake and initial speciation
No full textFormation of organometallic complexes in soil solution strongly influence metals phytoavailability. However, only few studies deal with the influence of metalspeciation both on plant uptake and genotoxicity. In the present study, Viciafaba seedlings were exposed for 6 h in controlled hydroponic conditions to 5 μM of lead nitrate alone and chelated to varying degrees by different organic ligands. Ethylenediaminetetraacetic acid and citric acid were, respectively, chosen as models of humic substances and low weight organic acids present in natural soil solutions. Visual Minteq software was used to estimate free lead cations concentration and ultimately to design the experimental layout. For all experimental conditions, both micronucleus test and measure of leaduptake by plants were finally performed. Chelation of Pb by EDTA, a strong chelator, dose-dependently increased the uptake in V. faba roots while its genotoxicity was significantly reduced, suggesting a protective role of EDTA. A weak correlation was observed between total lead concentration absorbed by roots and genotoxicity (r2=0.65). In contrast, a strong relationship (r2=0.93) exists between Pb2+ concentration in exposure media and genotoxicity in the experiment performed with EDTA. Citric acid induced labile organometallic complexes did not demonstrate any significant changes in leadgenotoxicity or uptake. These results demonstrate that metalspeciation knowledge could improve the interpretation of V. fabagenotoxicity test performed to test soil quality
The status of Orobanche crenata in Sicily and preliminary observations on Orobanche crenata susceptibility in Vicia faba
No full textSince more than 10 years we are recording Orobanche crenata populations variations and testing traditional remedies to assess their applicability in a low impact agriculture that may be applied also in developing countries. Starting from the observation that often in C Sicily dense fields of Broadbean show lower Broomrape infestation, we did some preliminary observations on Orobanche crenata susceptibility in Vicia faba var. faba and Vicia faba var. equina with different agricultural techniques. First results show a higher resistance of the latter sowed at higher densities
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